The present invention relates to a charged-particle beam exposure apparatus and device manufacturing method suitable for manufacturing devices such as a semiconductor device, micromachine, micro electron optical element, micro optical element, Fresnel lens, and binary optics.
Charged-particle beam exposure apparatuses such as an electron beam exposure apparatus and ion beam exposure apparatus exploit electron lenses. There is known a technique of forming an electron lens on a thin substrate (membrane) in order to downsize an electron optical system.
During exposure with a charged-particle beam, the interior of a charged-particle beam exposure apparatus, particularly the environment of an electron optical system which transmits a charged-particle beam keeps a high vacuum state in order to prevent attenuation of the charged-particle beam. To the contrary, when the apparatus does not operate or is to be maintained, the high vacuum state is canceled, and the interior is exposed to the atmospheric pressure. In adjusting the internal pressure of the charged-particle beam exposure apparatus, the pressure difference between the upper and lower surfaces of a substrate having an electron lens may change to deform the substrate. This deformation degrades the optical performance of the electron lens, and may damage the substrate in the worst case. The rigidity of the substrate decreases as the substrate becomes thinner for downsizing, so problem becomes more serious.
To prevent this problem, an abrupt pressure change is avoided by gently adjusting the pressure (supplying/exhausting air) for a long time. However, the long adjustment time decreases the effective availability (throughput) of the apparatus.
The present invention has been made in consideration of the above situation, and has as its object to prevent deformation of or damage to a substrate included in an electron optical system without degrading the performance or device manufacturing efficiency of a charged-particle beam exposure apparatus.
A charged-particle beam exposure apparatus according to the first aspect of the present invention comprises a charged-particle beam source, an electron optical system which irradiates a device material with the charged-particle beam emitted by the charged-particle beam source and includes a substrate having an aperture for transmitting the charged-particle beam, a cover which covers the charged-particle beam source and the electron optical system, an adjustment mechanism for adjusting a pressure in an internal space of the cover, and a relaxing mechanism for relaxing a pressure difference between upper and lower surfaces of the substrate upon a change in pressure in the internal space.
In the charged-particle beam exposure apparatus according to the first aspect of the present invention, the relaxing mechanism preferably has, e.g., a passage which allows a space facing the substrate to communicate with the internal space.
In the charged-particle beam exposure apparatus according to the first aspect of the present invention, the relaxing mechanism preferably has a valve at an end of the passage or midway along the passage.
In the charged-particle beam exposure apparatus according to the first aspect of the present invention, it is preferable that the apparatus further comprise a sensor for measuring information about the substrate, and that the controller control at least one of an opening degree of the valve and the adjustment mechanism on the basis of an output from the sensor. In this case, the sensor is preferably a pressure sensor for detecting the pressure difference between the upper and lower surfaces of the substrate, or a photosensor for optically detecting deformation of the substrate.
In the charged-particle beam exposure apparatus according to the first aspect of the present invention, it is preferable that the electron optical system have a plurality of substrates in which apertures for transmitting the charged-particle beam emitted by the charged-particle beam source are formed, and that the relaxing mechanism relax a pressure difference between upper and lower surfaces of each substrate.
In the charged-particle beam exposure apparatus according to the first aspect of the present invention, the relaxing mechanism preferably relaxes the pressure difference so as to prevent the pressure difference between the upper and lower surfaces of the substrate from exceeding a predetermined range.
In the charged-particle beam exposure apparatus according to the first aspect of the present invention, the controller preferably automatically executes control when the charged-particle beam exposure apparatus is turned on or off or maintained, or an emergency occurs.
In the charged-particle beam exposure apparatus according to the first aspect of the present invention, the substrate preferably has an electrode for applying a potential to the aperture of the substrate.
In the charged-particle beam exposure apparatus according to the first aspect of the present invention, the electron optical system preferably includes a plurality of substrates which have apertures for transmitting the charged-particle beam emitted by the charged-particle beam source and are arranged along a path of the charged-particle beam, and spacers disposed at all or some of intervals between the plurality of substrates. In this case, the spacers preferably have apertures at positions corresponding to the apertures formed in the plurality of substrates.
In the charged-particle beam exposure apparatus according to the first aspect of the present invention, it is preferable that the electron optical system include a plurality of substrates which have apertures for transmitting the charged-particle beam emitted by the charged-particle beam source and are arranged along a path of the charged-particle beam, and that all or some of the plurality of substrates be arranged to form a nested structure.
In the charged-particle beam exposure apparatus according to the first aspect of the present invention, it is preferable that the plurality of substrates respectively have membranes in which apertures are formed, and annular supports which support the membranes, that the electron optical system further include a base substrate which commonly supports the supports of the substrates which form the nested structure, and that the base substrate have an aperture which allows a space defined by the nested structure to communicate with the internal space of the cover.
A device manufacturing method according to the second aspect of the present invention comprises the steps of drawing a pattern on a device material by irradiating the device material with a charged-particle beam emitted by a charged-particle beam source via an electron optical system including a substrate having an aperture for transmitting the charged-particle beam, and relaxing a change in pressure difference between upper and lower surfaces of the substrate.
In the second aspect of the present invention, the step of relaxing the change in pressure difference preferably includes at least one of the step of adjusting a pressure in an internal space of a cover which covers the charged-particle beam source and the electron optical system, and the step of controlling a valve interposed between a space facing the substrate and the internal space of the cover which covers the charged-particle beam source and the electron optical system.
In the second aspect of the present invention, the device manufacturing method preferably further comprises the steps of applying a photosensitive agent to the device material, and developing the device material on which the pattern is drawn.
A device manufacturing method according to the third aspect of the present invention comprises the steps of installing a plurality of semiconductor manufacturing apparatuses including a charged-particle beam exposure apparatus in a factory, and manufacturing a semiconductor device by using the plurality of semiconductor manufacturing apparatuses, wherein the charged-particle beam exposure apparatus has a charged-particle beam source, an electron optical system which irradiates a device material with the charged-particle beam emitted by the charged-particle beam source and includes a substrate having an aperture for transmitting the charged-particle beam, a cover which covers the charged-particle beam source and the electron optical system, an adjustment mechanism for adjusting a pressure in an internal space of the cover, and a relaxing mechanism for relaxing a pressure difference between upper and lower surfaces of the substrate upon a change in pressure in the internal space.
The device manufacturing method according to the third aspect of the present invention preferably further comprises the steps of connecting the plurality of semiconductor manufacturing apparatuses via a local area network, connecting the local area network to an external network of the factory, acquiring information about the charged-particle beam exposure apparatus from a database on the external network by using the local area network and the external network, and controlling the charged-particle beam exposure apparatus on the basis of the acquired information.
A semiconductor manufacturing factory according to the fourth aspect of the present invention comprises a plurality of semiconductor manufacturing apparatuses including a charged-particle beam exposure apparatus, a local area network for connecting the plurality of semiconductor manufacturing apparatuses, and a gateway for connecting the local area network to an external network of the semiconductor manufacturing factory, wherein the charged-particle beam exposure apparatus has a charged-particle beam source, an electron optical system which irradiates a device material with the charged-particle beam emitted by the charged-particle beam source and includes a substrate having an aperture for transmitting the charged-particle beam, a cover which covers the charged-particle beam source and the electron optical system, an adjustment mechanism for adjusting a pressure in an internal space of the cover, and a relaxing-mechanism for relaxing a pressure difference between upper and lower surfaces of the substrate upon a change in pressure in the internal space.
A maintenance method for a charged-particle beam exposure apparatus according to the fifth aspect of the present invention comprises the steps of preparing a database for accumulating information about maintenance of the charged-particle beam exposure apparatus on an external network of a factory where the charged-particle beam exposure apparatus is installed, connecting the charged-particle beam exposure apparatus to a local area network in the factory, and maintaining the charged-particle beam exposure apparatus on the basis of the information accumulated in the database by using the external network and the local area network, wherein the charged-particle beam exposure apparatus has a charged-particle beam source, an electron optical system which irradiates a device material with the charged-particle beam emitted by the charged-particle beam source and includes a substrate having an aperture for transmitting the charged-particle beam, a cover which covers the charged-particle beam source and the electron optical system, an adjustment mechanism for adjusting a pressure in an internal space of the cover, and a relaxing mechanism for relaxing a pressure difference between upper and lower surfaces of the substrate upon a change in pressure in the internal space.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.